In comparison with liquid crystal displays, the organic light-emitting diodes of organic light-emitting displays have the advantages of low power consumption, low production cost, self-luminescence, wide visual angle and fast response speed, etc., and hence currently are widely applied in the display fields of mobile phones, PDAs, digital cameras and the like. Each pixel of the organic light-emitting display includes an organic light-emitting diode and a pixel circuit for driving the organic light-emitting diode to emit light for display.
A pixel circuit generally includes a drive transistor, a plurality of switch transistors and storage capacitors. Due to the manufacture process and device aging, etc., the characteristics of the drive transistor in the pixel circuit corresponding to the pixel may drift, for example, the threshold voltage may drift. Moreover, the drive transistor usually operates in a subthreshold region for a long time, which also tends to cause the characteristics of the drive transistor to drift. After the characteristics of the drive transistor drift, the characteristic curve may be twisted. The coincidence may not be completely realized even after a compensation, and thus the degrees of characteristic drifts for different drive transistors may be different, causing display mura and artifact, etc., so that the display effect of the whole image may be affected.